In the heavy quark limit, the wave function of a heavy-light meson has to be independent on the flavor and spin of the heavy quark. Therefore, the heavy-light mesons can be characterized by the light degrees of freedom, i.e., \(s_\ell =s_q +\ell \) , where \(s_q\)  and \(\ell \)  are the spin and orbital angular momentum of a light quark, respectively. In this case, the heavy-light mesons with the same light quark freedom can be degenerate. For example, the \(S\) -wave doublets \((B,B^\ast )\)  and \((\bar{B}, \bar{B}^\ast )\)  can be expressed in the matrix form, which are [1]}, [2]}, [3]}, [4]},
\(H_1&=&\frac{1+v\!\!\!\slash }{2}\Big [B^{\ast \mu }\gamma _\mu -B\gamma _5\Big ],\nonumber \\ H_2&=&\Big [\bar{B}^{\ast \mu }\gamma _\mu -\bar{B}\gamma _5\Big ]\frac{1+v\!\!\!\slash }{2},\) 
